(1) Field of the Invention
The present invention pertains to a trigger sprayer which is connectable to a separate liquid container, where the trigger sprayer has a trigger that is manually manipulated to pump liquid from the container, and dispense the liquid from the trigger sprayer as a spray, stream, or foam.
In particular, the present invention pertains to a venting membrane that is secured in the trigger sprayer to permit venting of air into the interior volume of the container as liquid is dispensed from the container, where the membrane is positioned in a cavity of the sprayer housing that protects the membrane.
(2) Description of the Related Art
The present invention pertains to a trigger sprayer which is connectable to a separate container containing a liquid. The trigger sprayer has a trigger that is manually manipulated to operate a pump in the trigger sprayer. The pump draws liquid from the liquid container, through the trigger sprayer, and dispenses the liquid from the trigger sprayer as a spray, stream, or foam.
There are many different systems employed in the construction of conventional trigger sprayers that allow for the venting of air to the interior of the liquid container connected to the trigger sprayer. The venting systems of trigger sprayers allow air to enter the container and occupy the container internal volume vacated by liquid dispensed from the container by the trigger sprayer. Venting of the container interior volume is required because the connection between the container and the trigger sprayer is typically a fluid-tight connection. This prevents the inadvertent leakage of the liquid contents of the container should the container and attached trigger sprayer be inverted or positioned on their sides. The fluid-tight connection between the container and the trigger sprayer is typically provided by a gasket positioned between the upper rim of a neck of the container and a bottom annular surface of the trigger sprayer housing. The connector that attaches the trigger sprayer to the container compresses the gasket between the container neck and the annular surface of the trigger sprayer housing, thereby providing the fluid-tight seal between the trigger sprayer and the container. However, the fluid-tight seal between the trigger sprayer and the container makes it difficult to vent the interior of the container as liquid is dispensed from the container. To maintain the fluid-tight connection between the trigger sprayer housing and the container, prior art venting systems have required elaborate constructions that add to the manufacturing costs of the trigger sprayer.
For example, one typical venting system employs a resilient diaphragm valve that covers a vent hole in the sprayer housing that communicates the interior of the container with the container exterior environment, and a plunger connected to the trigger of the trigger sprayer. On manipulation of the trigger, the plunger is inserted through the sprayer housing vent hole and presses against the diaphragm valve, moving the diaphragm valve away from the vent hole and thereby venting the interior of the container. This type of venting system has been found to be disadvantaged in that the resiliency of the material of the diaphragm often does not enable the diaphragm valve to immediately position itself over the vent hole when the plunger is retracted. This can result in liquid leaking from the container through the vent hole. Providing the resilient diaphragm valve and the plunger in the trigger sprayer construction also increases the cost of construction.
Another prior art venting system employs a small vent piston that reciprocates with the trigger and the pump piston of the trigger sprayer. The vent piston reciprocates in a vent chamber formed in the sprayer housing. As the vent piston is pushed into the vent chamber, the piston uncovers a vent hole that allows the container interior to be vented to the exterior environment. As the vent piston is pulled through the vent chamber and covers the vent hole, the container interior is again sealed from the exterior environment. The constructions of the these types of venting systems require that the sprayer housing be formed with an additional vent chamber, and that the trigger and/or pump piston be formed with an additional vent piston, increasing the manufacturing costs of the trigger sprayer.
What is needed to overcome these disadvantages of prior art trigger sprayers is a venting system that enables the interior of the container connected to the trigger sprayer to be vented, while maintaining the gasket fluid-tight seal between the trigger sprayer and without appreciably increasing the manufacturing costs of the trigger sprayer.